Brake control device



April 9- I M. s. GRAVES 2,152,686

BRAKE CONTROL DEVICE Filed N0v'. 3, 1937 $6.4. T155 A y? g :15

F 8 a 10 7 gwuwd'o r/ 7 177 .51 firaves;

Patented Apr. 4, '1939 UNITED STATES PATENT OFFlCE ICla-lm.

This invention relates to a device for controlling fluid pressure operated brakes such as are employed on motor vehicles. and more particularly pertains to a device for automatically preventing release of the brakes while the vehicle clutch is in a disengaged position.

An object 01' the invention is to provide a device of the above character embodying a selfclosing control valve arranged in the fluid presm sure delivery line of a fluid pressure operated brake system in which the valve is so arranged as to open under the flow oi fluid under pressure from the source of pressure supply to the brake mechanism and to automatically close on cessation 1 the flow of fluid pressure so as to prevent the release of the brakes in event the vehicle clutch is disengaged; the invention embodying a mechanism connected with the clutch operating mechanism for holding the control valve in its open position while the clutch mechanism is engaged and to release the control valve on placing the vehicle clutch in its released position.

Another object of the invention is to provide a control valve of the character above described so mounted and arranged as to be gravity operated to its closed position and which will so operate irrespective of any direction of inclination of the motor vehicle to which it is applied while the latter is in am upright position.

30 Another object is to provide a construction in the valve opening mechanism where connected with a clutch operated lever whereby on advancing the lever to effect disengagement oi the clutch mechanism, the control valve will close 33 almost immediately and which embodies a construction whereby when the valve operating mechanism has reached the limit of its movement on advance of the clutch control lever the latter may continue advancing to the limit oi 40 its stroke.

A further object is to provide an arrangement whereby the control valve may be operated and utilized as an emergency brake independent of the clutch control mechanism whereby the vehi- 45 cle operator may apply the fluid pressure operated brakes as when leaving the vehicle stand- (cl. lea-1s) With the foregoing objects in view, together with such other objects and advantagesas may subsequently appear, the invention is carried into effect as illustrated by way of example in the accompanying drawing in which: 5

Fig. 1 is a diagram in side elevation depicting the invention as applied:

Fig. 2 is a view in vertical section taken on the line 2-4 of Fig. 1 showing the construction and mode 01 operation of the control valve; m

Fig. 3 is a detail in section and elevation taken on the line 3-3 of Fig. 2 showing the manner in zhich the control valve is held in its open posi- Fig. 4 is a detail in section depicting a modified u form 01' the valve structure;

Fig. 5 is a detail in section demonstrating an-- other form of, the valve structure.

Referring to the drawing more specifically A indicates generally the master cylinder of a hydraulic brake system which is of the usual type and embodies a cylinder and piston (not shown) for creating a fluid pressure in the system in efl'ecting application of the brakes; the piston being attached to a connecting rod 6 o'peratively connected to a brake pedal 1.

Leading from the master cylinder A is a fluid conductor 8 which leads to the wheel brakes B (only one being diagrammatically illustrated) in which conductor is arranged a control valve indicated generally at c.

The control valve 0 embodies an upstanding cylindrical valve housing 9 formed intermediate its. ends with a valve seat Ill and fitted with an upwardly opening 'valve D which is adapted to normally gravitate to a closed position on the seat II. The housing 9 is fitted at its lower end with a cap ll formed with a nipple l2 opening to the interior of the lower end portion of the housing and to which nipple is attached by a 40 coupling ii the length of the conduit 8 leading from the fluid pressure supply in the master cylinder A. The upper end of the housing 0 is fitted with a cap I on which is formed a nipple l5 opening to the interior of the upper end por- 46 tion of the housing 9 and to which nipple is attached by a coupling it the portion of the conduit Q leading to the brakes B.

Means are provided for holding the valve D in an open position which means embodies a rock shalt l1 extending laterally into the housing S through a packing gland I! carried on the latter, and on which shait is mounted interiorly oi the housing 8 an upstanding finger I! which when disposed in an upright position will serve to prevent the valve D from advancing to its closed position on the valve seat II, but which finger I3 is adapted on turning the rock shaft II to be positioned out of engagement with the valve D to allow the latter to gravitate to its closed position on the seat It.

' The rock shaft I1 is fitted at its outer end with a crank arm 23 to which is attached a link 2| leading to and connecting with a clutch operating lever 22; the connection between the'link 2| and lever'22 comprising a pin 23 on the latter extending into a longitudinally extending slot 24 formed on an outer end section a of the link 2! which end section slidably telescopes a tube b 13- formed on the link and to which tube the section a is connected by a helical spring 9.

Connecting with the upper end of the arm 23 is a pull spring 25 leading from a bracket 23' on the master cylinder A which spring acts to normally maintain the arm 23 in a retracted position with the finger l3 disposed to hold the valve D in an open position. When the arm 23 is in its retracted position the pin 23 on the clutch lever 22 will be disposed at the forward end of the slot 24 as shown in Fig. 1.

Leading from the upper end of the arm 23 op-' posite the spring 25 is a wire 21 which passes through a supporting tube 23 and connects with an upwardly extending hand lever 29 pivoted at 30 to a suitable support 3|, which lever is ppsitioned convenient to the reach of the operator and is arranged for positioning at an upward inclination from its pivot 30 to either side of the vertical.

The valve D preferably embodies a ball 32 as shown in Figs. 2 and 3 formed of steel or other suitable metal of suflicient'weight to readily move to its seated position when permitted so to do. However, in some instances the valve D may comprise a leaf valve in the form of a disk 33 as shown in Fig. 4; the disk being formed with a finger 34 engaging a pin 35 on the valve housing I to provide a-hinged connection with the latter on which the leaf 33 may swing vertically relative to the valve seat II. A projection 33 is formed on the under side of the disk 33 and positioned to be engaged by the finger I! on the rock shaft H in such manner that when the finger I3 is in its vertically extending position the disk 33 will be held in an open position.

In some instances the valve D may embody a semi-spherical valve body 31 as shown in Fig.

which is formed with a hooked finger 33 engaging a pin 39 carried by the housing 3 to afi'ord a pivotal mounting for the valve body 31 so that the latter may swing vertically relative to the valve seat III. In this instance the rounded under side of the valve body 31 is disposed for engagement by the upper end of the finger I! on the rock shaft l1 so as to be held in open podtion when the finger I9 is disposed in its vertical position.

Normally the parts are disposed as shown in full lines in the drawing, that is, with the valve D held in its open position by the upstanding finger is under the urge of the spring 25 exerting a pull on the arm 20, that is, while the clutch lever 22 is in the normally retracted position it occupies when the clutch controlled thereby is in its engaged position. While the valve D is thus maintained open fiow of the brake operating fiuid may occur in either direction through the valve housing 3. but when the'valve D is in its closed position such-fiow is restricted to the di-, rection leading from the master cylinder A to the I brakes B. It follows that in the operation of the invention, when the. clutch lever 22 is disposed in its normal retracted position with the clutch in its engaged position, and the valve D held in its open position, the vehicle brakes B may be freely applied and released byoperation of the brake lever 1 in the usual manner; but on depressing the clutch lever to release the clutch then the rock shaft II will be turned by the forward movement of the clutch lever through the link 2 I, so as to move the finger II from beneath the valve D thereby allowing the latter to advance to its cloud position. When this occurs and the brakes are applied while the clutch lever is advanced and the clutch is disengaged, release of the brakes will be prevented by reason of the valve D then being closed so as tocomfine the brake operating fluid in the conduit 3 between the valve and the brakes B. until such time as the clutch lever is released to re-engage the clutch.

During forward operation of' the clutch lever it may be advanced beyond the extent of the movement necessary to eifect closing of the valve D by reason of the resilient connection aiiorded in the link 2| by the. spring c which permits the lever to advance after the arm 23 of the control valve 0 is brought to rest.

When it is desired to elect closing of the valve D independent of the clutch lever 22, the lever 23 is advanced from the position shown in full lines in Fig. 1 to the position indicated in dotted lines, thereby eiiecting a pull on the wire 21 such as to advance the valve arm 23 in opposition to the spring 25 and thereby move the finger is from beneath the valve D. Forward movement of the arm under this operation is permitted by reason of the pin and slot connection 23-24 between the link 2| and the clutch lever; this connection allowing the link 2| to advance independently of the clutch lever. By thus operating the lever 29 the device will then act as an emergency brake since on then operating foot lever 1 to apply the brakes the latter will be held in their applied position independent of the brake lever 1 and will then be only subject to release on restoring the hand lever 29 to its advanced position. In operating the lever 29 it will be held in its retracted position in opposition to the spring by reason of the connection between the wire 21 and the lever 29 being passed beyond the vertical center of movement of the lever.

In thus utilizing the device as an emergency brake the valve D may be set in readiness for operation to prevent release of the brakes at any time previous to operation of the brake lever 1.

A feature of the invention resides in arranging the valve housing 3 in a vertical position sons to insure the valve D moving under the influence of gravity to a closedposition on the valve being released by the finger I 9 irrespective of any inclination of the vehicle to which the device is applied in any direction, as long as the vehicle is in an upright position.

It will be understood that the control mechanism herein set forth is applicable for use in brake systems employing either liquid or air as a fluid pressure operating medium.

It is manifest'that the spring 0 has a tension exceeding that of the valve operating spring 25 so that on advance of the clutch lever 22 the spring c will overcome the spring 23.

While I have shown and described a specific embodiment of the invention I do not limit myself to the exact details of construction or' arrangement shown but may employ such modifications said housing beneath said valve, a finger on said as come within the purview of the accompanying claim.

I claim:

In a control device for fluid pressure operated brake systems including a conduit for transmission fluid and connecting a source of pressure supply and a brake operating mechanism, an upstanding valve housing in said conduit having a vertically extending passage leading therethrough, an upwardly opening valve in said housing normally closing said passage under the influence of gravity, a rock shaft extending into rock shaft engageahle with said valve for holding the latter in its open position, an arm on said rock shaft, a clutch operating lever, connections between said lever and said am arranged to actuate said rock shaft to move said finger out of engagement with said valve on depression of the lever, and spring means connected to said arm yieldably maintaining said rock shaft disposed with the finger thereon in the valve opening pom sition.

MARK S. GRAVESl 

